Simulation of the Forging Process Incorporating Strain-Induced Phase Transformation Using the Finite Volume Method

Abstract

A method to simulate the forging process and corresponding strain-induced austenitic-martensite phase transformation is formulated in the Eulerian description and its feasibility is examined. The method uses finite volume meshes for tracking material deformation and an automatically refined facet surface to accurately trace the free surface of the deforming material. By means of this finite volume method, an approach has been developed in the framework of metallo-thermo-mechanics to simulate metallic structure, temperature and stress/strain in the forging process associated with phase transformation. The incremental expression on the formulation of the kinetics equation is derived from Tsuta and Cortes' model. A mixture rule is adopted to evaluate the aggregate flow stress of the austenite-martensite affected by the respective flow stresses and phase transformation. This approach has been implemented in the commercial computer program MSC. SuperForge. This is the first report in which the fundamental fr amework is stated and the applicability of the developed method is confirmed using experimental results of the forging of a cylindrical billet. Some practical forging applications are demonstrated in the second report.

A modified level set approach to 2D modeling of dynamic recrystallization

“…Driven by the rate of macroscopic plastic deformation, eq. (18) represents a constant rate of nucleation law, corresponding to the proportional nucleation model in [41,42], also employed in [43,44]. It should be noted, however, that the rate of nucleation in the present model is constant at a given temperature but will change with changing temperature.…”

Tensile Deformation Induced Texture Transformation in Austenitic Stainless Steel

“…Renewed interest in a better understanding of this mechanism and its effect on texture evolution results from the need of reliable input parameters for the development of computer codes simulating various metallurgical forming processes (Ding et al, 2001). Since the -transformation is martensitic the crystallographic orientation relation between the starting and transformed phases is necessarily a key element in any model of the transformation mechanism.…”

Simulation of strain induced austenite‐martensite transformation

“…The volume of strain-induced transformation is a function of equivalent plastic strainε p and temperature T . The strain and strain-rate hardening of stainless steel in austenite state is given with a power law [5]. We assume that the strain resistance of the stainless steel σ d during austenite-martensite transformation depends on the strain resistance of the steel in austenite state σ A d and on the martensite volume fraction ξ M :…”

“…According to [5] the two volume fractions, austenite ξ A and martensite ξ M , develop under the restriction ξ A + ξ M = 1. The volume of strain-induced transformation is a function of equivalent plastic strainε p and temperature T .…”